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| Illustration 1 | g00516915 |
Schematic for the Power Train Hydraulic System (1) Priority valve (2) Power train oil pump (3) Steering and brake control valve (4) Power train oil filter (5) Selector and pressure control valve (7) Sump (main case) (8) Line for the steering clutch and brake lubrication (9) Torque converter (10) Torque converter outlet relief valve (11) Line for transmission lubrication (12) Oil cooler (13) Sump (torque converter housing) (A) Transmission and steering clutch control section (B) Lubrication section (C) Pump drive and torque converter scavenge section | |
The hydraulic system for the power train is supplied by a three-section pump (2) . The pump operates only when the engine is running. The pump is fastened to the torque converter housing. Lubrication section (B) uses oil from the common reservoir in main case (7) . The oil is removed through a screen. Oil from section (B) is sent to power train oil filter (4) . The oil from power train oil filter (4) provides lubrication for the steering clutches and brakes. This oil supplies a portion of the transmission lubrication also. This oil is the supply oil for section (A) of the hydraulic pump. Pump drive and torque converter scavenge section (C) removes oil from torque converter sump (13) . The oil is then sent to main case (7) .
The oil from section (A) is sent to steering and brake control valve (3) . This oil is sent to priority valve (1) also. The priority valve makes sure that oil is available for steering and braking before the transmission is operated. The priority valve is set to open to the transmission controls at 2825 kPa (410 psi). The oil travels from the priority valve to the transmission hydraulic controls.
Transmission selector and pressure control valve (5) controls the pressure and flow of the oil to the transmission clutches for engagement. The ratio valve which is inside of this control valve controls the inlet pressure to torque converter (9) . The ratio valve is set at 918 ± 55 kPa (133 ± 8 psi).
Oil travels from torque converter (9) through torque converter outlet relief valve (10) . Torque converter outlet relief valve (10) maintains the pressure inside the converter at approximately 290 kPa (42 psi). The oil then goes to oil cooler (12) . After going through the oil cooler, the oil returns for lubrication and cooling of the transmission.